184 research outputs found

    Ultra-low temperature structure determination of a Mn12 single-molecule magnet and the interplay between lattice solvent and structural disorder

    Get PDF
    We have determined the ultra-low temperature crystal structure of the archetypal single-molecule magnet (SMM) [Mn12O12(O2CMe)16(H2O)4]·4H2O·2MeCO2H (1) at 2 K, by using a combination of single-crystal X-ray and single-crystal neutron diffraction. This is the first structural study of any SMM in the same temperature regime where slow magnetic relaxation occurs. We reveal an additional hydrogen bonding interaction between the {Mn12} cluster and its solvent of crystallisation, which shows how the lattice solvent transmits disorder to the acetate ligands in the {Mn12} complex. Unusual quantum properties observed in 1 have long been attributed to disorder. Hence, we studied the desolvation products of 1, in order to understand precisely the influence of lattice solvent on the structure of the cluster. We present two new axially symmetric structures corresponding to different levels of desolvation of 1, [Mn12O12(O2CMe)16(H2O)4]·4H2O (2) and [Mn12O12(O2CMe)16(H2O)4] (3). In 2, removal of acetic acid of crystallisation largely resolves positional disorder in the affected acetate ligands, whereas removal of lattice water molecules further resolves the acetate ligand disorder in 3. Due to the absence of acetic acid of crystallisation, both 2 and 3 have true, unbroken S4 symmetry, showing for the first time that it is possible to prepare fully axial Mn12–acetate analogues from 1, via single-crystal to single-crystal transformations

    Assessment of Sleep Disturbances and Exhaustion in Mothers of Children With Atopic Dermatitis.

    Get PDF
    Importance: The well-being and development of children is strongly influenced by parents' physical and psychosocial health. Data from small, clinic-based studies suggest that sleep loss may be common in parents of children with atopic dermatitis (AD), but longitudinal population-based studies are lacking. Objectives: To compare sleep disturbances over time between mothers of children with and without AD and to determine whether these disturbances are associated with the child's disease severity and the child's sleep disturbances. Design, Setting, and Participants: In the ongoing Avon Longitudinal Study of Parents and Children, all pregnant women residing in Avon, United Kingdom, with an expected delivery date between April 1, 1991, and December 31, 1992, were recruited. Analyses for this study, a secondary analysis of this cohort, were performed from September 2017 to September 2018. Mother-child pairs were followed up with a time-varying measure of child AD activity and severity and self-reported maternal sleep measures repeated at multiple time points between child ages 6 months and 11 years. Main Outcomes and Measures: Time-varying binary measures of maternal sleep duration (<6 vs ≥6 hours per night), difficulty falling asleep, early morning awakening, subjectively insufficient sleep, and daytime exhaustion. Results: The study followed up 13 988 mother-child pairs from birth for a median duration of 11 (interquartile range, 7-11) years. Among the cohort, 11 585 of 13 972 mothers (82.9%) were aged 21 to 34 years and 12 001 of 12 324 (97.4%) were of white race/ethnicity; 7220 of 13 978 children (51.7%) were male. Sleep duration (adjusted odds ratio [AOR], 1.09; 95% CI, 0.90-1.32) and early morning awakenings (AOR, 1.16; 95% CI, 0.93-1.46) were similar between mothers of children with and without AD. In contrast, mothers of children with AD were more likely to report difficulty falling asleep (AOR, 1.36; 95% CI, 1.01-1.83), subjectively insufficient sleep (AOR, 1.43; 95% CI, 1.24-1.66), and daytime exhaustion (AOR, 1.41; 95% CI, 1.12-1.78) independent of the child's comorbid asthma and/or allergic rhinitis. For all measures, worse child AD severity was associated with worse maternal sleep outcomes. The magnitude and significance of the associations were largely unchanged after adjustment for child sleep disturbances. Conclusions and Relevance: Mothers of children with AD reported difficulty falling asleep, subjectively insufficient sleep, and daytime exhaustion throughout the first 11 years of childhood. However, child sleep disturbances did not fully explain maternal sleep disturbances, and future research should investigate other mechanisms. In caring for children with AD, clinicians should consider maternal sleep disturbances and caregiver fatigue

    Association of Atopic Dermatitis With Sleep Quality in Children.

    Get PDF
    Importance: Pruritus, a hallmark of atopic dermatitis (AD), is thought to disrupt sleep, yet little is known about how variations in disease activity and severity of this common childhood condition may be associated with sleep patterns over time. Objective: To determine whether children with active AD have impaired sleep duration and quality at multiple time points throughout childhood and whether disease severity affects sleep outcomes. Design, Setting, and Participants: This longitudinal cohort study used data of children enrolled in the Avon Longitudinal Study of Parents and Children, a population-based birth cohort in Avon, United Kingdom. Participants were children (N = 13 988) alive at 1 year and followed up with repeated measures of self-reported AD and sleep through 16 years of age. This study was based on data collected from 1990 to 2008. Data analysis was performed from September 2017 to September 2018. Main Outcomes and Measures: Standardized measure of sleep duration and composite measure of sleep quality, including nighttime awakenings, early morning awakenings, difficulty falling asleep, and nightmares, were repeated at multiple time points between 2 and 16 years of age. Results: The study sample comprised 13 988 children (7220 male [51.6%]) followed up for a median (interquartile range [IQR]) duration of 11 (5-14) years. Of this total, 4938 children (35.3%) met the definition of having atopic dermatitis between 2 and 16 years of age. Total sleep duration was similar between children with active AD and without AD at all ages, and the average estimated difference across childhood was a clinically negligible difference of 2 minutes less per day for children with AD (95% CI, -4 to 0 minutes). In contrast, children with active AD were more likely to report worse sleep quality at all time points, with a nearly 50% higher odds of experiencing more sleep-quality disturbances (adjusted odds ratio [aOR], 1.48; 95% CI, 1.33 to 1.66). Children with more severe active disease (quite bad or very bad AD: aOR, 1.68; 95% CI, 1.42 to 1.98) and with comorbid asthma or allergic rhinitis (aOR, 1.79; 95% CI, 1.54 to 2.09) had worse sleep quality. However, even children with mild AD (OR, 1.40; 95% CI, 1.27 to 1.54) or inactive AD (OR, 1.41; 95% CI, 1.28 to 1.55) had statistically significantly increased odds of impaired sleep quality. Conclusions and Relevance: Atopic dermatitis appeared to be associated with impaired sleep quality throughout childhood; thus, it is suggested that clinicians should consider sleep quality among all children with AD, especially those with comorbid asthma or allergic rhinitis and severe disease, and that interventions to improve sleep quality are needed

    How does climate change affect emergent properties of aquatic ecosystems?

    Get PDF
    Emergent properties of ecosystems are community attributes, such as structure and function, that arise from connections and interactions (e.g., predator–prey, competition) among populations, species, or assemblages that, when viewed together, provide a holistic representation that is more than the sum of its individual parts. Climate change is altering emergent properties of aquatic ecosystems through component responses, a combination of shifts in species range, phenology, distribution, and productivity, which lead to novel ecosystems that have no historical analog. The reshuffling, restructuring, and rewiring of aquatic ecosystems due to climate impacts are of high concern for natural resource management and conservation as these changes can lead to species extinctions and reductions in ecosystem services. Overall, we found that substantial progress has been made to advance our understanding of how climate change is affecting emergent properties of aquatic ecosystems. However, responses are incredibly complex, and high uncertainty remains for how systems will reorganize and function over the coming decades. This cross-system perspective summarizes the state of knowledge of climate-driven emergent properties in aquatic habitats with case studies that highlight mechanisms of change, observed or anticipated outcomes, as well as insights into confounding non-climate effects, research tools, and management approaches to advance the field

    Developmental phosphoproteomics identifies the kinase CK2 as a driver of Hedgehog signaling and a therapeutic target in medulloblastoma

    Get PDF
    A major limitation of targeted cancer therapy is the rapid emergence of drug resistance, which often arises through mutations at or downstream of the drug target or through intrinsic resistance of subpopulations of tumor cells. Medulloblastoma (MB), the most common pediatric brain tumor, is no exception, and MBs that are driven by sonic hedgehog (SHH) signaling are particularly aggressive and drug-resistant. To find new drug targets and therapeutics for MB that may be less susceptible to common resistance mechanisms, we used a developmental phosphoproteomics approach in murine granule neuron precursors (GNPs), the developmental cell of origin of MB. The protein kinase CK2 emerged as a driver of hundreds of phosphorylation events during the proliferative, MB-like stage of GNP growth, including the phosphorylation of three of the eight proteins commonly amplified in MB. CK2 was critical to the stabilization and activity of the transcription factor GLI2, a late downstream effector in SHH signaling. CK2 inhibitors decreased the viability of primary SHH-type MB patient cells in culture and blocked the growth of murine MB tumors that were resistant to currently available Hh inhibitors, thereby extending the survival of tumor-bearing mice. Because of structural interactions, one CK2 inhibitor (CX-4945) inhibited both wild-type and mutant CK2, indicating that this drug may avoid at least one common mode of acquired resistance. These findings suggest that CK2 inhibitors may be effective for treating patients with MB and show how phosphoproteomics may be used to gain insight into developmental biology and pathology

    A Review of Pink Salmon in the Pacific, Arctic, and Atlantic Oceans

    Get PDF
    The Northern Hemisphere Pink Salmon Expert Group Meeting was held on October 2–3, 2022 in Vancouver, Canada, immediately preceding the International Year of the Salmon (IYS) Synthesis Symposium. The rapid expansion of pink salmon was the theme for the meeting, and experts came together to discuss the current state of knowledge for pink salmon. Specific topics of focus included the range expansion into the Atlantic and Arctic oceans, trends in distribution and abundance, research and monitoring approaches, potential inter-specific interactions, mitigation efforts, and plans for future collaborations. The outcomes of the meeting were presented at the IYS Synthesis Symposium and are further disseminated through this NPAFC Technical Report. The Executive Summary section of this report provides a brief background, a condensed overview of each topic, and concludes with overarching takeaway messages that are intended to guide future collaborations.publishedVersio

    A Review of Pink Salmon in the Pacific, Arctic, and Atlantic Oceans

    Get PDF
    The Northern Hemisphere Pink Salmon Expert Group Meeting was held on October 2–3, 2022 in Vancouver, Canada, immediately preceding the International Year of the Salmon (IYS) Synthesis Symposium. The rapid expansion of pink salmon was the theme for the meeting, and experts came together to discuss the current state of knowledge for pink salmon. Specific topics of focus included the range expansion into the Atlantic and Arctic oceans, trends in distribution and abundance, research and monitoring approaches, potential inter-specific interactions, mitigation efforts, and plans for future collaborations. The outcomes of the meeting were presented at the IYS Synthesis Symposium and are further disseminated through this NPAFC Technical Report. The Executive Summary section of this report provides a brief background, a condensed overview of each topic, and concludes with overarching takeaway messages that are intended to guide future collaborations.publishedVersio

    Standardizing data reporting in the research community to enhance the utility of open data for SARS-CoV-2 wastewater surveillance

    Get PDF
    SARS-CoV-2 RNA detection in wastewater is being rapidly developed and adopted as a public health monitoring tool worldwide. With wastewater surveillance programs being implemented across many different scales and by many different stakeholders, it is critical that data collected and shared are accompanied by an appropriate minimal amount of meta-information to enable meaningful interpretation and use of this new information source and intercomparison across datasets. While some databases are being developed for specific surveillance programs locally, regionally, nationally, and internationally, common globally-adopted data standards have not yet been established within the research community. Establishing such standards will require national and international consensus on what meta-information should accompany SARS-CoV-2 wastewater measurements. To establish a recommendation on minimum information to accompany reporting of SARS-CoV-2 occurrence in wastewater for the research community, the United States National Science Foundation (NSF) Research Coordination Network on Wastewater Surveillance for SARS-CoV-2 hosted a workshop in February 2021 with participants from academia, government agencies, private companies, wastewater utilities, public health laboratories, and research institutes. This report presents the primary two outcomes of the workshop: (i) a recommendation on the set of minimum meta-information that is needed to confidently interpret wastewater SARS-CoV-2 data, and (ii) insights from workshop discussions on how to improve standardization of data reporting

    A graphical vector autoregressive modelling approach to the analysis of electronic diary data

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>In recent years, electronic diaries are increasingly used in medical research and practice to investigate patients' processes and fluctuations in symptoms over time. To model dynamic dependence structures and feedback mechanisms between symptom-relevant variables, a multivariate time series method has to be applied.</p> <p>Methods</p> <p>We propose to analyse the temporal interrelationships among the variables by a structural modelling approach based on graphical vector autoregressive (VAR) models. We give a comprehensive description of the underlying concepts and explain how the dependence structure can be recovered from electronic diary data by a search over suitable constrained (graphical) VAR models.</p> <p>Results</p> <p>The graphical VAR approach is applied to the electronic diary data of 35 obese patients with and without binge eating disorder (BED). The dynamic relationships for the two subgroups between eating behaviour, depression, anxiety and eating control are visualized in two path diagrams. Results show that the two subgroups of obese patients with and without BED are distinguishable by the temporal patterns which influence their respective eating behaviours.</p> <p>Conclusion</p> <p>The use of the graphical VAR approach for the analysis of electronic diary data leads to a deeper insight into patient's dynamics and dependence structures. An increasing use of this modelling approach could lead to a better understanding of complex psychological and physiological mechanisms in different areas of medical care and research.</p
    corecore